3LY7

Crystal structure of the periplasmic domain of CadC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure of the sensory domain of Escherichia coli CadC, a member of the ToxR-like protein family.

Eichinger, A.Haneburger, I.Koller, C.Jung, K.Skerra, A.

(2011) Protein Sci. 20: 656-669

  • DOI: 10.1002/pro.594
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The membrane-integral transcriptional activator CadC comprises sensory and transcriptional regulatory functions within one polypeptide chain. Its C-terminal periplasmic domain, CadC(pd), is responsible for sensing of environmental pH as well as for b ...

    The membrane-integral transcriptional activator CadC comprises sensory and transcriptional regulatory functions within one polypeptide chain. Its C-terminal periplasmic domain, CadC(pd), is responsible for sensing of environmental pH as well as for binding of the feedback inhibitor cadaverine. Here we describe the crystal structure of CadC(pd) (residues 188-512) solved at a resolution of 1.8 Å via multiple wavelength anomalous dispersion (MAD) using a ReCl(6)(2-) derivative. CadC(pd) reveals a novel fold comprising two subdomains: an N-terminal subdomain dominated by a β-sheet in contact with three α-helices and a C-terminal subdomain formed by an eleven-membered α-helical bundle, which is oriented almost perpendicular to the helices in the first subdomain. Further to the native protein, crystal structures were also solved for its variants D471N and D471E, which show functionally different behavior in pH sensing. Interestingly, in the heavy metal derivative of CadC(pd) used for MAD phasing a ReCl(6)(2-) ion was found in a cavity located between the two subdomains. Amino acid side chains that coordinate this complex ion are conserved in CadC homologues from various bacterial species, suggesting a function of the cavity in the binding of cadaverine, which was supported by docking studies. Notably, CadC(pd) forms a homo-dimer in solution, which can be explained by an extended, albeit rather polar interface between two symmetry-related monomers in the crystal structure. The occurrence of several acidic residues in this region suggests protonation-dependent changes in the mode of dimerization, which could eventually trigger transcriptional activation by CadC in the bacterial cytoplasm.


    Organizational Affiliation

    Munich Center for Integrated Protein Science and Lehrstuhl für Biologische Chemie, Technische Universität München, Freising-Weihenstephan, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Transcriptional activator cadC
A
372Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: cadC
Find proteins for P23890 (Escherichia coli (strain K12))
Go to UniProtKB:  P23890
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.191 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 83.898α = 90.00
b = 83.898β = 90.00
c = 199.090γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
MAR345dtbdata collection
PHASERphasing
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-02-09
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance